Close to a week after its third service outage in five months, M1 today released a media statement with updates on its preliminary findings and the immediate measures that it is taking to enhance the mobile network.

The cause of the call processing software issue originated from a pair of mobile site switches which operated in an unstable manner. This led to intermittent connection problems between the switches and customer databases, and set off a chain reaction.

As customers need to be verified by the telco's network before making voice calls, the intermittent connection disrupted the authentication process which led to a build up of unsuccessful authentication attempts. Network resources were hogged up and this caused congestion at the customer databases.

The congestion surged to another network layer, typing up even more network resources and preventing customers from making or receiving calls. As the congestion spread across the network, the telco had to clear it across the layers for services to be restored.

M1 is reconfiguring the site switches to eliminate congestion that may arise due to unstable intermittent connections. In addition, it is deploying a software enhancement to better manage sudden and unexpected extreme traffic conditions. The telco also will be appointing an independent expert to review its network architecture and connectivity to further enhance network performance.

“We are continually upgrading our network to deliver better customer experience and improve network resiliency. With a more sophisticated network, it has inevitably increased the level of complexity in troubleshooting. I sincerely apologise for the inconvenience caused to our customers from this incident,” said Ms Karen Kooi, Chief Executive Officer, M1 Limited.